Process of making insulating materials.



\JJ. COMPOSITIONS,

COATING OR PLASTIC Cross Reference 039 .970 UNITED STATES PA E T OFFICE.

EMILE HEMMING, OF PASSAIC, NEW JERSEY. ASSIGNOB TO HEMMING MANUIFACTUB-ING COMPANY, OF GARFIELD, NEW JERSEY, A CORPORATION OF NEW JERSEY.

PROCESS OF IAKING DITBULATING MATERIALS.

No Drawing.

Specification Letters .Patent.

Application filed April 12. 1911. Serial No. 620,549.

Patented Oct. 1, 1912.

lb all whom it may concern:-

Be itlmown that 1, Emma HEMMING, a citizen of Switzerland, residin atPassaic, in the county of Passaic and tate of New 5 Jersey, haveinvented certain new and useful Im rovements in Processes of MakingInsulat ng Materials, of which the following is a specification.

This invention relates to the process of making compressed fireproofmaterials for electrical insulating and other purposes, com osed ofasbestos and a oementitious bin er such as Portland cement which hardensby hydration and setting Theresuiting articles, when thoroughly dried,may be rendered substantially waterproof by impregnation with abituminous or resinous substance such as ,coal tar pitch, and a solvent,followed byy'drying or baking to drive of! the volatile matter, at thiswaterproofing treatment is not an essential part of m invention and insome instances 1s omitte My invention relates especially to the natureand order of the operations employed in hydrating the material, and itsob)cct is mainly to attain a thorough hardening without anfytetendencyof the articles to swell or warp a r being compressed or molded. Thetotal hydration is divided into stages, and owing to the absorbentquality of the asbestos, the latter reacts hysically with the water andthe cement uring the initial hydration, and again during the subsequenthydration, in a beneficial manner which I believe to be novel.

In carrying out my process I may take, by way of example, 1 part byweight of ashestos, preferably in the round or powdered form, and 3parts of a inder such as Portland cement. to which, if the mold is ofcomplicated form, a small quantity of a solution of silicate of soda(water glass) may be added to give sharp definition; mix thesethoroughly together, add enough water to make a thick paste; and thensubject the paste to heavy pressure .in a suitable mold.

The water may be added before the mixture is placed in the mold or whileit. is in the mold, but its quantisy should be insulticient to produceany great degree of fluidity in the paste. It mafv for example bepresent in the proportion 0 about 10 to 12 per cent. of the total weightof the moistened mixture. If only about 10 per cent. of water is usedare non-absorbent.

for the initial hydration, it will practically all remain in the moldedarticle after the latter has been compressed. If more water is used,some of it will generally be expressed by the molding pressure. Thequantity remainmgior contained in the article however, while an cient toproduce considerable hardness when the molded article is dried, isinsufiicient to fully utilize the setting properties of the cement.Therefore after the article is removed from the mold I allow it to dryand set sufficiently to insure the retention of its form and reventsubsequent swelling or warping, an I then soak the article in orsprinkle it with water for a further period of time until it isthoroughly set or hardened, after which it is all awed to dry. Thematerial in this condition ma be used for various purposes without furthment, but where waterproof qualities are desired, the articles mayfurther be impregnated. preferably in a vacuum, with a suitable reslnousor bituminous. substance such er treatas coal tar pitch and a solvent,the impregnatcd article being then baked in an oven to drive oil thevolatile constituents of the impregnating substance.

I am aware that the steps of initial hydration of a mixture of sand orthe like and hydraulic cement. followed by molding. drying, furtherhydration and further drying are not new. But sand and similar materialsThe asbestos which I employ, being highly absorbent. acts lilcc a spongeto retain a portion of the-water during the initial hydration. andyields it slo\vl v to the cement In the molded article as fast as thecement can take it up. thereby cnabling the water to be used at first ingreater effective quantity and producing greater hardness and strengthto resist the cracking and distorting tendency of the subsequenthydration. When the final wetting is administered. the now driedasbestos fibers act a a multiform capillary conduit rmeating the entiresubstance of the mo] ed article, and conseguently the final hydrationand setting are more quickly, uniformly and thoroughl effected thanwhere a non-absorbent filler is employed. There is also the addedstrength due to the interlocking qualities of the asbestos, which myroduct exhibits in common with other pro nets of asbestos and hardenedcement, which have not, howsorbed by the asbestos and cement and yieldedup from the asbestos to the cementas the latter hardens whereby themoisture is 15 distributed uniformly throughout the article by saidasbestos and produces a complete hydration ad set of the cement. Intestimony whereof I have hereunto set my hand in the resence of twosubscribing 2 witnesses, this eleventh day of April, 1911.

EMILE HEMMING.

Witnesses:

R. M. PmRsoN,

G. BLAKE.

